joining me from new york presbyterian nbc's chief science and health correspondent robert bazell. what do we know this morning, bob? >> reporter: well, chris, since we've been talking about this last night we don't have a lot of information. we just have this one statement from secretary clinton's office and the hospital is not saying anything. a lot of doctors are telling me the information in that statement is a bit contradictory. here's why. they say that she has a blood clot that stemmed from a concussion she got several weeks ago. but the problem is, blood clots that stem from concussions don't usually get treated with blood thinning drugs which is what they say they're doing here. either she has a concussion someplace else that may not -- excuse me -- a blood clot someplace else that may not be related to the concussion or there is more to her health that we don't know about. they say they're watching her closely for a couple days. we will have to continue to watch ourselves to see what the situation is but right now all we know is that she is in this hospital. she's under o